30 C. and 70 C. postal stamp with overprint in type I as correctly franked mixed franking on cover from "Ghyvelde 28. 7. 40" to Dunkerque with reverse arrival postmark from 29. 7. 40, in perfect condition condition, signed Zierer and certificate with photograph autumn VP (2014) : "the condition is perfect. The stamps are only in very small number of pieces recorded, so that they very rare are. ", Michel 1. 000.-